Extracting　Cr,　Ni　and　Fe　from　the　sludge　of　stainless　steel　acid　washing　wastewater　with　ammonia　and　sulfuric　acid　was　carried　out.　The　effects　of　reaction　time,　liquid-to-solid　ratio,　temperature,　ammonia　concentration　and　the　volume　of　sulfuric　acid　on　the　extraction　ratio　were　investigated.　In　ammonium　leaching　process,　the　maximum　leaching　rate　of　Ni　is　30.8%,　and　on　the　same　condition　the　leaching　rate　of　Cr　and　Fe　is　2.21%　and　0.016%,　respectively.　In　acid　leaching　process,　the　maximum　leaching　rate　of　Ni,　Fe　and　Cr　is　78.1%,　30.24%　and　26.54%　respectively.　The　factor　that　leads　to　the　low　extracting　ratio　maybe　the　suspended　substance　in　the　sludge　which　exists　as　particulate　matter　in　original　wastewater　before.　In　acid　leaching　process　metals　can　lowly　be　leached　out　because　of　the　surface　passivation　of　chromium　in　these　particulate　matter.　It　can　be　concluded　that　regular　leaching　reaction　is　not　a　proper　method　for　extracting　Cr,　Ni　and　Fe　from　the　sludge　of　stainless　steel　acid　wastewater.　©　2011　IEEE.